Obesity and inactivity are significant public health concerns. Environmental variables may have substantial influence on activity patterns of US adolescents and young adults. However, there has been minimal empirical research on the role of physical environment factors in decreasing activity and increasing obesity at the population level. The proposed career development grant will focus on modifiable factors in the physical environment (e.g., public and public gyms, recreation facilities, crime rates) that explain the differential distribution of physical activity and overweight patterns by ethnicity and socioeconomic status. The proposed research will generate and link contemporaneous geographic locations of respondents and, physical environment variables to data from two exceptional and unique longitudinal datasets, the National, Longitudinal Study of Adolescent Health and the Coronary Artery Risk Development in Young Adults Study. Specific aims include: 1) the development and validation of new physical environment measures from existing databases that will be linked to respondents' geographic locations and added to both datasets; and 2) the investigation of the effect of physical environment variables on physical activity and overweight patterns of adolescents and young adults to test the hypothesis that environmental and sociodemographic factors predict persistence in patterns of activity and/or overweight prevalence from adolescence to adulthood. The proposed study will make a unique contribution through the innovative use of community-level data linked to individual data and the use of a multidisciplinary approach melding spatial analysis methodologies, such as Geographic Information Systems, with traditional epidemiological methods. The proposed career development award will build the applicant's skills in two areas: sophisticated spatial analysis and longitudinal analysis. These data will develop a research niche in an area that is just beginning to draw attention from public health researchers. The institutional environment, including the UNC School of Public Health and the Carolina Population Center, as well as experts in spatial and longitudinal analysis, will foster collaborative work and develop skills necessary to successfully compete for future research funding.